Question

I have a DDL and Button which when clicked create a dynamic table; all controls are within an UpdatePanel.

Outside the panel I have 2 buttons which should be hidden until the table is created.
If the buttons start as visible = false and then I set them to true after I click the GO button from the UpdatePanel, they never become visible

If I add a second UpdatePanel and put the 2 buttons in there it sort of works but I always get this error when clicking on either button:

Microsoft JScript runtime error: Sys.WebForms.PageRequestManagerParserErrorException: 
The message received from the server could not be parsed.

How to fix that?

Answer 1

Move the two Buttons inside Update Panel. Only controls in the update panel get updated in an Ajax call. That is, if you want to alter any control’s state through codebehind in an Ajax call you will have to include it inside your Update panel. You cannot change controls outside Update panel in an Ajax call.

UPDATE
You need event handlers for this. Make the Button visible=true; and set their visibility:hidden, then change them as below when your call is completed.

<script type="text/javascript" language="javascript">
    Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(beginRequestHandle);
      Sys.WebForms.PageRequestManager.getInstance().add_endRequest(endRequestHandle);
      function beginRequestHandle(sender, Args) {
      //Do something when call begins.
        }

function endRequestHandle(sender, Args) {
document.getElementById("Button1").style.visibility = "visible";
document.getElementById("Button2").style.visibility = "visible";
}
      </script>